Replace BMW Key Battery It might be time to replace your battery if your BMW key won't allow you to open your car or turn on the engine. It's a simple fix. Simply remove the key fob, replace the battery, and then gently put it back. Follow these steps and https://car-key-reprogramming77131.blogunteer.com/29465665/11-ways-to-fully-redesign-your-bmw-3-series-key-fob